Patent GB-1101548-A (GB)
Title: Improvements in or relating to axle mechanisms
IPC: F16H63/30
Filed: 1966-08-03
Abstract: 1,101,548. Change speed control. EATON AXLES Ltd. 3 Aug., 1966 [4 Aug., 1965], No. 34883/66. Heading F2D. [Also in Division B7] Relates to a control for a multispeed vehicle axle drive assembly comprising two, rearward and forward, axles 11, 12 driven in parallel through an interconnecting differential 21, wherein at least one of the axles includes a gear ratio shift mechanism actuable to vary the output speed of said one axle, and the interconnecting differential 21 is lockable. In such an assembly, to prevent excessive gear wear, a valve 133 prevents axle upshift when the interconnecting differential 21 is locked. As shown, the axles 11, 12 are each two-speed and have their individual ratios separately selectable to provide three effective ratios, viz.: Low (Lo): both axles low ratio; Intermediate (Int): one axle low and the other high ratio; and High (Hi): both axles high ratio. A manual distributer valve 131 selectively energizes or vents one or both of pneumatically-actuated, spring- returned servomotors 18, 19 effecting upshift and downshift in the axles 11, 12. The interconnecting differential 21 is locked by energization of a pneumatically-actuated, spring- returned servomotor 22 (Fig. 9) only when both axles are in low ratio. Pistons of the servomotors 18, 19 are connected to shift sleeves of the respective axles 11, 12 through lever systems, shifts by energization and venting of the servomotors taking place only on reduction of transmitted torque below a predetermined value. The manual distributer valve 131 comprises a rotary plate spring-plunger detained in three positions, viz.: Lo, in which lines 130, 117a respectively connected to the servomotors 19, 18 are vented; Int., in which the line 130 is connected indirectly to a supply tank 200b, the line 117a remaining vented; and Hi, in which both of the lines 130, 117a are connected indirectly to the tank 200b. The distributer valve 131 is mounted on the shift lever of the vehicle change speed gear 23 which is connected to the input of the interconnecting differential 21. The pressurizing and venting lines to and from the valve 131, e.g. of nylon, may be harnessed to the shift lever or the latter may comprise a hollow tube enclosing said lines. The lines 130, 117a are connected to their respective servomotors through quick release valves 104, 103 and lines 101, 35, the valves 104, 103 venting the lines 101, 35 upon predetermined pressure drop in the lines 130, 117a. The interconnecting differential locking servomotor 22 is energized from the tank 200b through a manual, cam-actuated, valve 215 and through a sensing valve 80 which is so actuable by a cam connected to the shift lever system of the axle 12, that it is open only when said axle is in low ratio. The locking means for the interconnecting differential 21 comprises a toothed sleeve 60 (Fig. 9) which is splined on the input shaft 61 of the differential 21 and is lockingly shifted by the servomotor 22, by way of a yoke 65, to engage teeth 63 on a gear 64 of the differential 21. The tank 200b is connected to the distributer valve 131 through the valve 133 which is so actuable by a cam portion of the piston-rod 70 of the servomotor 22 that it is open to allow upshifts in the axles only when the interconnecting differential 21 is unlocked.